可压缩气体中的三维粘性液体空心柱射流稳定性分析

针对可压缩气体介质中的空心圆柱形粘性液体射流建立了三维模型,并对射流的空间稳定性进行了分析.影响扰动增长率的无量纲参数有Reynolds数、Weber数、气液密度比、气体介质相对于射流运动参考系的Mach数及空心柱内半径与液膜厚度比.Reynolds数在液体射流雾化过程中始终起着不稳定性的作用,但它对不稳定扰动波波数的范围没有影响.扰动增长率及不稳定扰动波波数的范围均随Weber数的增加明显增大.气液密度比在液体射流雾化过程中具有加速射流雾化的作用.气体介质相对于射流运动参考系的Mach数对射流雾化过程具有不稳定性的作用,也就是说气体的可压缩性在液体射流雾化过程中具有不稳定性的作用,它的增加会促进雾化过程的进行.当空心柱内半径与液膜厚度比较小时,它在雾化过程中具有不稳定性的作用,反之则具有稳定性的作用.

Three-Dimensional Stability of an Annular Viscous Liquid Jet in Compressible Gas

A three-dimensional model of an annular viscous liquid jet injected in a compressible gas media was developed, and its spatial stability analysis was conducted. The primary parameters that govern the growth rates of disturbances are the Reynolds number, the Weber number, the density ratio between the gas and liquid, the Mach number of the gas with respect to the frame of reference moving jet and the ratio of inner radius to the thickness of liquid sheet. The Reynolds number always tends to promote the instabilities of liquid jets, but it has no effect on the range of unstable wave numbers. The growth rates of disturbances and the range of unstable wave numbers are increased remarkably with the Weber number increasing. The density ratio plays an action to improve the atomization of liquid jets. As the Mach number of the ambient gas is increased, the instability of liquid jets is increased, namely the compressibility of the gas media enhances the jet instability. When the ratio of inner radius to the thickness of liquid sheet is small, it acts on the instability in the process of the jet, while becomes larger, it reduces the jet instability.